Abstract
Advanced internal combustion engine calibration to comply with, both, customer wishes and emission goals is in need of reliable and easy-to-handle measurement equipment. As the calibration of soot emissions (smoke) is one of the key parameters of engine and exhaust aftertreatment application, IAV developed a new in-situ smokemonitoring device, the IAV Opacity Meter EOM 200 (EOM).
The EOM was designed for the application at the engine test-bench as well as at the tailpipe of test vehicles powered by diesel or gasoline direct injection engines in a compact set-up comprising a separated control unit featuring the electronics and light source and controlled via a remote from the measuring head featuring the optical measurement path to be installed directly at the tailpipe. This work describes the correlation of the opacity meter with commercially available soot monitoring instruments. It could be shown, that the correlation between several opacity meters with the EOM are very good and do potentially correlate with filter smoke numbers under the applied conditions. Furthermore, the time-response of the EOM is very fast as no probe sampling is required for the opacity detection. The crosssensitivity of the EOM to NO2 emissions was shown to be negligible up to several hundreds of ppm. In order to avoid water condensation on the windows at cold engine conditions, electrically heated windows were installed into the measuring head yielding a reliable soot measurement even at cold engine conditions. The signal drift over time and temperature is comparatively low at +/- 0.5% opacity.
Keywords:opacity meter, soot emission, in-situ smoke monitoring, smoke calibration